JPH06206223A - Thermoplastic prepreg unidirectional fabric and laminated molded object thereof - Google Patents

Abstract

PURPOSE:To obtain a flexible molding material having good moldability by respectively using a tape like prepreg impregnated with a thermoplastic resin and a fiber constituted of the same thermoplastic resin or a separate thermoplastic resin having the compatibility therewith as warp and weft yarns. CONSTITUTION:Either one of a tow prepreg obtained by forming an integrated tow of continuous reinforcing fibers impregnated with a thermoplastic resin into a tape shape and a fiber composed of the same thermoplastic resin or a separate thermoplastic resin having the compatibility therewith is used as warp yarn and the other one of them is used as weft yarn to constitute a thermoplastic unidirectional fabric. A plurality of the thermoplastic prepreg unidirectional fabrics are superposed one upon another to be molded to constitute a thermoplastic prepreg unidirectional fabric laminate. By this constitution, the molding material of a thermoplastic composite material capable of molding having flexibility, good handling properties and good moldability and capable of producing a void free molded product can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic prepreg unidirectional woven fabric and a laminated molded product thereof.

More specifically, a molding material for a thermoplastic composite material having flexibility and flexibility (drapeability), which is easy to handle, and a light weight, high strength, obtained by molding a laminate thereof,
The present invention relates to a highly elastic thermoplastic composite material molded body.

The thermoplastic prepreg unidirectional woven fabric of the present invention has excellent features such that it is easy to handle and set in a mold, and is suitable for curved surface molding, and the resulting molded product has good physical properties. From exhibiting automotive materials,
It can be used as electrical / electronic materials, building materials, aircraft materials, etc.

[0004]

2. Description of the Related Art Composite materials using a thermoplastic resin as a matrix have been in the limelight in recent years because of their excellent toughness, moldability, storage characteristics, repairability and recyclability.

The basic molding material used for molding a thermoplastic composite material is a thermoplastic prepreg sheet, and a composite material can be obtained by laminating and molding these. Such a thermoplastic prepreg sheet has drawbacks such as being rigid and difficult to handle, and being difficult to fit in a curved surface shape, as compared with conventionally well-known thermosetting prepreg sheets such as epoxy resin.

As a method for improving these, there have been proposed methods such as the Commingled Yarn and Coeven Cross method in which a matrix thermoplastic resin is made into a fiber to form a composite with a reinforcing fiber, and a method in which it is made into a powder form and coated / attached to the reinforcing fiber. ing.

Although these methods can solve the above-mentioned drawbacks of the thermoplastic prepreg sheet and provide a flexible and flexible molding material, at the same time, the resin is impregnated into the fiber and the molding is performed at the time of molding. It is necessary to do.

Therefore, in order to obtain a void-free molded product, a high molding pressure and a long molding time are required, which causes a problem that the fiber arrangement is disturbed and the resin is easily deteriorated.

On the other hand, in order to avoid these problems, if the molding conditions (low molding pressure, short molding time, etc.) of the usual thermoplastic prepreg sheet in which the resin is pre-impregnated are applied, the impregnation is insufficient and voids are generated. Many molded products can be obtained,
It cannot be put to practical use.

[0010]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide molding materials for thermoplastic composites and the resulting laminates thereof which are flexible and easy to handle and which provide molded articles having good moldability and voids. An object of the present invention is to solve the problems of the prior art by providing a molded body.

[0011]

SUMMARY OF THE INVENTION The present invention is intended to achieve the above-mentioned object by providing a thermoplastic prepreg unidirectional woven fabric and a laminated molded product thereof. More specifically, it is made of a tow prepreg taped by impregnating a single tow of continuous reinforcing fibers with a thermoplastic resin and another thermoplastic resin having the same or compatibility with the thermoplastic resin. It is intended to provide a thermoplastic prepreg unidirectional woven fabric using one of the fibers as a warp yarn and the other as a weft yarn, and a thermoplastic prepreg unidirectional woven fabric laminated product obtained by molding a plurality of such woven fabrics. .

The tow prepreg used in the present invention is a tape formed by impregnating one tow of continuous reinforcing fibers with a thermoplastic resin. In this case, the impregnation method is not particularly limited, and various conventionally known methods can be adopted. That is, the method of removing the solvent and water after impregnating the resin into a solution or emulsion, the method of melting the resin after impregnating the resin into powder, film, or thread and introducing it between fibers, and the method of monomer or oligomer in the fiber Method of impregnating into the fiber and then polymerizing, method of directly impregnating the molten resin into the fiber (for example, by superposing the molten sheet resin and the fiber and then press-fitting the resin into the fiber, into the molten resin) Such as those that are pulled through the die after introducing the fiber).
Among these, the melt drawing method, which is performed by using a crosshead die attached to an extruder, is a typical method (the present inventors have already filed as Japanese Patent Application No. 4-227706).

As the continuous reinforcing fiber described in the present invention, glass fiber, carbon fiber, aramid fiber, polyethylene fiber, liquid crystal polymer fiber, polyphenylene sulfide fiber, alumina fiber, silicon carbide fiber, metal fiber or a combination thereof is known. Can be given. These fibers (monofilaments) generally have a diameter of 4 to 20 μm. These fibers are usually subjected to a known surface treatment in order to improve the affinity with the resin.

In the present invention, the continuous reinforcing fibers are used in the form of a single tow. Many tows, typically 1000
It is a bundle of about 15,000 monofilaments. A known sizing agent is used in this case.

Examples of the thermoplastic resin of the present invention include the well-known thermoplastic resins. For example, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polymethyl methacrylate, nylon 6, nylon 66, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyphenylene oxide, polyacetal, polysulfone, polyether sulfone, polyarylate, polyphenylene sulfide, polyether Examples include ether ketone, liquid crystal aromatic polyester, polyimide, and their copolymers, modified products, and blends of two or more of the above. In addition, when using these, it is safe to add Kochi's additives, modifiers, fillers, and the like.

The tow prepreg of the present invention has a tape shape. As a general shape, the width is 1 to 10 mm and the thickness is 100 to 500 μm. In the production of prepreg fabric, the uniformity of width is particularly required, and the variation must be within ± 10%. Also, from the viewpoint of weavability, a material having an excessively large thickness is not suitable and the above range is preferable. Regarding its composition,
In the whole, continuous reinforcing fibers are 15 to 65% by volume, preferably 20 to 60% by volume, and thermoplastic resin is 35 to 85% by volume, preferably 40 to 80% by volume.

If the proportion of the continuous reinforcing fibers is less than 15% by volume, the resulting molded article has poor physical properties and cannot be put to practical use. On the other hand, if the above value is more than 65% by volume, the molding is difficult and it is difficult to obtain a good molded product.

On the other hand, the present invention uses fibers made of another thermoplastic resin having the same or compatibility with the above-mentioned thermoplastic resin. Here, "another thermoplastic resin having compatibility" means a material which is compatible with the above-mentioned thermoplastic resin in a heat-melted state when the thermoplastic prepreg unidirectional woven fabric of the present invention is molded. The most typical example is a thermoplastic resin having the same molecular species as that of the thermoplastic resin but having a different molecular weight, molecular weight distribution, additives, or the like. The fiber described here may be either a monofilament or a multifilament in which a large number of them are collected, and a so-called flat yarn whose cross-sectional shape of the monofilament is a circle, an ellipse or a rectangle can be used. The size is preferably 5 to 100 μm in the case of a circle, 1 to 10 mm in width and 10 to 200 μm in the case of a rectangle. The number of filaments in case of multi-filament is 1
It is about 0 to 1000.

According to the present invention, a thermoplastic prepreg unidirectional woven fabric is produced by using one of the tow prepreg and the fiber made of a thermoplastic resin as a warp yarn and the other as a weft yarn. Regarding the woven structure, flat biaxial woven fabrics such as plain weave, twill weave, and satin weave are mentioned. Speaking of yarn density, first of all, it is necessary to arrange the tow prepregs so that there is no overlap or gap. If there are overlaps or gaps, it is easy to cause fiber disorder and poor dispersion when they are molded. Next, the density of the fiber made of the thermoplastic resin should be such that the arranged tow prepregs can maintain their shape so as not to fall apart. However, if the density is too high, the content of the continuous reinforcing fibers in the composite material decreases, resulting in unsatisfactory physical properties. About 1 to 10 yarns per 25 mm width are good. In the present invention, as described above,
Either the prepreg or the fiber made of a thermoplastic resin may be used as the warp or weft. Use one for the warp and the other for the weft. Since the fibers made of the above-mentioned thermoplastic resin are melted and become a part of the matrix when these fabrics are heated, the thermoplastic prepreg unidirectional fabric of the present invention is formed into a unidirectional composite material by molding. It was given. Therefore, these can be handled in the same manner as conventional one-way prepreg sheets. The fibers that can be used are not particularly limited,
When the tow prepreg is used for the weft, a rapier loom is suitable.

The above is a thermoplastic prepreg unidirectional woven fabric, but another aspect of the present invention is a thermoplastic prepreg unidirectional woven fabric obtained by molding a plurality of these thermoplastic prepreg unidirectional woven fabrics. It is a laminated compact. As this molding method, known methods such as autoclave molding, hot press molding, stamping molding, and diaphragm molding can be applied. Molding conditions such as temperature, pressure and time vary depending on the thermoplastic prepreg unidirectional woven fabric (resin, continuous reinforcing fiber, composition, woven structure, shape, etc.) used, the laminated construction and the molding method used. It cannot be said that the optimum conditions should be selected so that the fiber arrangement is not disturbed, voids, and resin deterioration does not occur. or,
In particular, if the resin is crystalline, care must be taken because the cooling conditions have a significant effect on the physical properties.

The thermoplastic prepreg unidirectional woven laminate molding of the present invention thus obtained has a composition of continuous reinforcing fibers of 15 to 65% by volume, preferably 20 to 60% by volume, and thermoplastic resin of 35 to 85% by volume, preferably 40 to 80% by volume. If the proportion of the continuous reinforcing fibers is less than 15% by volume, the physical properties of the molded article will be low, and if it exceeds 65% by volume, voids and poor dispersion of the fibers will occur, which is not desirable.

[0022]

EXAMPLES The contents of the present invention will be described in detail below with reference to examples and comparative examples. This section describes the evaluation method used in all the examples described here. (1) Fiber content rate (volume content rate) It was obtained by thermally decomposing the resin. (2) 0 ° Bending Property Using a universal material testing machine model 1185 manufactured by Instron Co., Ltd., the test was performed according to ASTM D790 (three-point bending). (3) Interlaminar Shear Strength The same apparatus as in (2) was used and the measurement was performed according to ASTM D2344 (short beam method). (4) Resin impregnation state A laminated molded body cut into a length of about 1 cm was embedded with an unsaturated polyester resin, and the cross section was polished using a polishing machine (system sample polishing machine L-1000 manufactured by Japan Geoscience Co., Ltd.). After precision polishing, it was observed with an optical microscope.

Reference Example 1 : Production of thermoplastic tow prepreg Glass fiber (manufactured by Nippon Electric Glass Co., Ltd., fiber diameter 17 μm, 115
0 tex, aminosilane treatment), low molecular weight maleic anhydride modified polypropylene (manufactured by Sanyo Kasei, brand name Umex 1001, number average molecular weight 15,000, acid value 26 mg KO
H / g) and polypropylene (UBE Polypro J950HK, UBE Industries, Ltd., melt flow index 50), and the method described in Japanese Patent Application No. 4-227706 has a width of 7 mm, a thickness of 200 μm and a glass fiber content of 33%.
Of tow prepreg was manufactured.

Example 1 A polypropylene multifilament (monofilament diameter 30 μm
m, the number of filaments 120) was used as a weft to prepare a plain weave fabric with a hand-woven machine. Weaving density is 3.5 warps /
It was 25 mm and the weft yarn was 1.3 threads / 25 mm. This woven fabric was flexible and rich in drapeability, and the shape was firmly held, so the handling property was good.

Example 2 A plain-woven fabric was prepared in the same manner as in Example 1 except that the weave density of the weft yarn was changed to 4 threads / 25 mm. This woven fabric was flexible and rich in drapeability, and the shape was firmly held, so the handling property was good.

Example 3 A plain weave fabric was prepared in the same manner as in Example 1, except that the tow prepreg was used as the weft and the polypropylene multifilament was used as the warp (weave density: 10 warps / 25 mm, 3.5 wefts / 25 mm). It was made. This woven fabric was flexible and rich in drapeability, and the shape was firmly held, so the handling property was good.

Example 4 A plain weave fabric was produced in the same manner as in Example 1 except that polypropylene flat yarn (width: 5 mm, thickness: 20 μm) was used instead of the polypropylene multifilament, and the weave density was 5/25 mm. . This fabric is
The handling was good because it was flexible and rich in drape, and the shape was firmly held.

Example 5 A plain weave fabric was produced in the same manner as in Example 4 except that the weave density of the polypropylene flat yarn was 3 yarns / 25 mm. This woven fabric was flexible and rich in drapeability, and the shape was firmly held, so the handling property was good.

COMPARATIVE EXAMPLE 1 The tow prepreg produced in Reference Example 1 was wound on a drum (diameter 400 mm) while heating (250 ° C.) using a hot blaster by a drum winding method (tape winding method) (peripheral speed 3 m / Min), width 35
A unidirectional sheet having a length of 0 mm, a length of 1260 mm and a thickness of 250 μm was produced. This sheet was rigid and not supple.

Example 6 Twelve pieces of the thermoplastic prepreg unidirectional woven fabric prepared in Example 1 were laminated so that the glass fibers were aligned in one direction, and press-molded to obtain a unidirectional laminated material.
The molding conditions are as follows:
Pressurize at 1 MPa for 1 minute, then pressurize 2
It was to introduce water at 0 ° C. into a mold to cool and solidify. The evaluation results of the obtained laminated material are shown in Table 1.

[0031]

[Table 1]

Unidirectional laminated materials were formed in exactly the same manner as in Examples 7 to 6 except that the woven fabrics produced in Examples 2 to 5 were used as the thermoplastic prepreg unidirectional fabrics. The evaluation results of the obtained laminated material are shown in Table 1.

Reference Example 2 : Molding and Evaluation of Unidirectional Sheet Laminated Material In Example 6, pressing was performed in the same manner as in Example 6 except that the thermoplastic prepreg unidirectional fabric was replaced by the unidirectional sheet prepared in Comparative Example 1. Molding was performed to obtain a unidirectional laminated material.
The evaluation results are shown in Table 1.

As is clear from the above examples, the thermoplastic prepreg unidirectional woven fabric of the present invention is soft and has drapeability, and also has good handleability. And, these can be molded products without voids in a short time at low pressure. Further, the obtained molded product exhibits the same physical properties as those of conventionally known unidirectional sheet laminated materials.

[0035]

EFFECTS OF THE INVENTION According to the present invention, a molded product having flexibility, good handling property, good moldability (low pressure, short time molding) and no void can be obtained, which was impossible by the conventional technique. It is possible to provide a thermoplastic composite molding material that can be manufactured. Since such composite materials have excellent physical properties, they are suitable for use as automobile materials, electric / electronic materials, building materials, aircraft materials, and the like.

Claims (2)

[Claims] 1. A tow prepreg obtained by impregnating a single tow of continuous reinforcing fibers with a thermoplastic resin to form a tape, and another thermoplastic resin having the same or compatibility with the thermoplastic resin. Thermoplastic prepreg unidirectional fabric using one of the fibers as warp and the other as weft. 2. A tow prepreg obtained by impregnating a single tow of continuous reinforcing fibers with a thermoplastic resin to form a tape, and another thermoplastic resin having the same or compatibility as the thermoplastic resin. A thermoplastic prepreg unidirectional woven laminated product obtained by stacking a plurality of thermoplastic prepreg unidirectional woven fabrics, one of which is used as a warp yarn and the other as a weft yarn.